Most battery powered or portable electronic devices typically include a battery as the power source for the device. In the case of electronic devices with memory, or other devices that require continuous operation, there exists the problem of replacing the battery once it is exhausted, while at the same time providing continuous operation or maintaining the memory contents during the battery removal process. One solution to the battery removal process is the use of a battery back-up. Essentially, this involves the addition of a second battery in parallel with the primary battery. When the primary battery is removed and replaced, the back-up battery provides power until a new battery is inserted. Once the new battery is inserted, it provides primary power. The back-up battery is then disconnected and conserved for future back-up operations. While this solution provides continuous operation and maintains memory contents, it nevertheless introduces additional cost and complexity. Specifically, an additional back-up battery is required, along with any required switching electronics and contacts. This latter requirement may be somewhat onerous since oftentimes the back-up battery is situated in a somewhat inaccessible internal location to prevent inadvertent dislodging of the back-up battery. The use of a back-up battery also requires more space.
An alternative approach to the battery removal process is the use of a large capacitor as a temporary power device during the battery removal process. In this approach, a large capacitor is constantly maintained in a charged condition by the battery. When it comes time to replace the battery and the battery is removed, the charged capacitor is used to provide power until the new battery is installed. Again, this approach is undesirable because of the increased cost, space and complexity associated with the capacitor and the required components. Also, this approach provides only a limited solution, since most capacitors used for this application are able to provide power only for a limited time, typically on the order of 5-15 seconds.
Therefore, there exists a need for a simple, yet effective, method for battery removal which provides continuous power without substantially increasing cost or complexity.